Re: [Discuss-gnuradio] SNR(Signal to Noise Ratio) Value in DQPSK Implementation

[Tom Rondeau]

On Thu, Sep 1, 2011 at 1:20 PM, waqasme <address@hidden> wrote:
>
> Hi All,
> Does anyone know where we can change the Signal to noise ratio value in GNU
> radio companion. i have made one DQPSK simulation for image transfer and now
> i want to check the transmission and reception of the image at different SNR
> values. I am unable to find any signal block where i can change the SNR
> value .?? Please if any one can help i will be very grateful.
>
> Regards,
> Waq

You will want to add a Gaussian noise source and a add block to add
AWGN, or you can use the channel_model block. To set the SNR, you will
first have to calculate the signal power in your simulation and from
their, determine the noise power for your desired SNR. The convert the
noise power to an amplitude, which is what the noise source block
takes. Look in gnuradio-examples/python/digital/benchmark_loopback.py
to see an example of these calculations.

Tom